The present invention relates generally to patient monitoring devices, and more particularly, to improvements in sensor pads for use with patient monitoring systems for notifying medical personnel and caregivers in the event a patient or ward leaves a bed or chair unattended.
Patient monitoring devices are employed in hospitals and nursing homes, and the like to alert staff if a patient or ward gets out of bed or a chair unattended, (or falls out of bed or chair), or in the case of a infant, is removed from a crib by a unauthorized person. Referring to FIG. 1, a typical patient monitoring system includes a controller 10 adapted to receive a signal from a detecting pad 12 which typically is hard wired to controller 10 through line 14. Controller 10 typically includes a power switch and a display 16, and typically includes a visual and audible alarm 18. Alternatively, sensor pad 12 maybe battery powered, and include a built in radio transmitter for sending a signal to controller 10.
Referring to FIG. 2, sensor pad 12 typically comprises a pressure pad or membrane switch type sensor comprising a pair of flexible dielectric sheets or membranes 20, 22 joined to one another at their periphery 24 by an adhesive or by thermal welding. Formed inwardly of periphery 4 on facing surfaces of sheets 20 and 22 are conductor strips 26 and 28 respectfully. Conductor strips 26 and 28 typically are formed of screen printed carbon or the like and together form the two poles of a membrane or pressure switch which is normally xe2x80x9copenxe2x80x9d, and which completes a circuit when subjected to sufficient pressure. Pad 12 also may include a pressure sensitive adhesive 30 and release sheet 32 on the back thereof so that the pad maybe fixed in place on a mattress or chair pad. Sensor pads in accordance with the foregoing are available commercially from several sources including Secure Care Products, Inc. of Concord N.H.
The present invention provides an improvement in sensor pads of the like above discussed. More particularly, the present invention provides a sensor pad in which open circuit patterns are printed on one surface of a first dielectric sheet, while a plurality of switch closures are printed on the surface of a second dielectric sheet facing the first sheet. The second dielectric sheet includes a plurality of raised areas or pods on which the switch closures are printed. The switches are in a normally open position, and are closed by pressure from the weight of a patient.
Still are the features and advantages the present invention will be seen from the following detailed description taken in conjunction with the accompanying drawings wherein: